1. Field of the Invention
The present invention relates to a plant growth medium made from a zeolite coated with nanophase Fe oxide which can be used in a variety of different end applications, e.g., being loaded with a complete spectrum of agronutrients necessary for plant growth, making the medium useful for a variety of floricultural and horticultural applications.
2. Description of the Prior Art
One area in which a horticultural/floricultural adjunct, e.g., a complete plant growth medium of the type under consideration, could be used to advantage is in the area of “urban horticulture.” Urban horticulture is the practice of growing ornamental plants, vegetables, fruits, and turf in an urban setting. These plants may be grown in native soil, highly-modified beds (manufactured soil), or containers. Abundant and healthy urban vegetation is an important resource for mitigating the urban heat island phenomena that is becoming increasingly prevalent in large metropolitan areas (Lo, C. P., D. A. Quattrochi, and J. C. Luvall. 1997. “Application of high-resolution thermal infrared remote sensing and GIS to assess the urban heat island effect.” J. Remote Sensing. 18:287-304). In terms of food production, urban vegetable gardening can play a small but important role in helping supply cities with a fresh source of food products. Such a “companion food security movement,” is touted as promoting urban-rural linkages and has been demonstrated to be an important part of the urban life in fulfilling the food needs, psychological and physiological health, social cohesion, crime prevention, recreation, and life satisfaction, especially of low-income communities (Hynes, H. P. and G. Howe. 1993. International Conference on Urban Horticulture. http://www.actahort.org/books/643/643—21.htm, Aug. 24, 2004). A dimension of the urban horticulture that has not been given adequate attention so far, however, is the availability or lack of availability of a good local support system by the city governments and/or the enhancement of its service capability to the community at large. A suitable plant growth medium, of the type under consideration, could help to address these needs and could be used in urban horticulture to save precious and scarce water resources, as well as avoiding excess fertilizer usage, thereby preventing nitrogen and phosphorous run off into the municipal sewer system.
One use for a plant growth medium of the type under consideration would be for container growing of plants in urban horticulture. There are multiple reasons why it is important to have container grown plants in an urban setting. Homeowners often have limited garden space or have soil that is not well suited for growing horticultural plants. Homes and businesses are often constructed on marginal soils that have unsuitable physical and chemical properties, such as high pH, or high clay contents, making them impermeable and slow to drain. It is often difficult to grow healthy plants in urban soils because the soils contain large amounts of construction debris, such as mortar, bricks, sheetrock, plywood, plastic, and other leftovers from the home building/improvement activities (North Carolina Cooperative Extension Service. 2004. Residential Landscaping. Publication AG-248. http://ipm.ncsu.edu/urban/horticulture/res_landscaping.html, Aug. 24, 2004). Growing plants in containers protects the homeowner from distasteful or unsuccessful modification of the landscape that might discourage potential home buyers in the event that the property goes on sale. In order for cities to mitigate the harmful heat island phenomena, it will become increasingly important that they be able to grow plants in containers so that they can establish cooling vegetative zones in such places as roadsides, parking lots, and rooftops.
Because the plants are grown in containers, one can prepare the container-mix to the exact requirements of a plant for better growth and production (Ohio State University Extension. 2004. “Growing Cucumbers, Peppers, Squash and Tomatoes In Containers.” Fact Sheet HYG-1645-94. http://ohioline.osu.edu/hyg-fact/1000/1645.html, accessed Aug. 24, 2004). Accordingly, the mix (soil-mix/potting-mix/container-mix) should be loose and well drained, and should contain a generous amount of organic matter. This is typically achieved by mixing potting soil, perlite, sphagnum moss, and compost in appropriate proportions. Garden soil is generally avoided because it is much heavier than organic blends and it might contain damaging plant pests, but if garden soil is used, as some would prefer, it is important to use appropriate amendments to make sure the final mix has physical characteristics suitable for plant growth.
Despite the above recognized needs, presently available natural and synthetic plant growth mediums have suffered from various deficiencies or disadvantages when considered for use in the urban setting. For example, sphagnum peat moss is a widely used and important component of potting mixes sold in United States horticulture markets. The principal use of peat is to provide the bulky organic component of the growing medium. Sphagnum peat moss is less commonly used as a minor component of amendments for improving soil physical properties.
In 1999, the U.S. consumed on the order of 1.5 million tons of peat as one of the potting mix ingredients. Currently, U.S. imports peat from Canada and Ireland, but due to environmental restriction in these countries these imports may be restricted or even eliminated. Furthermore, peat is biodegradable and has a limited life span.
Another common potting mix ingredient is perlite, a mineral that has negative exchange sites and does not have the ability to retain anions.
A need exists, therefore, for a horticultural/floricultural adjunct, e.g., a complete plant growth medium which is superior to both peat and perlite in that the zeolite component in the mix is non biodegradable, helps buffer the mix, and retains both cationic and anionic plant nutrients.